Process of clarifying oil



Feb. 26, 1929.

' C. VAN BRUNT PROCESS OF CLARIFYING OIL Original Filed March 5, 1924 Inventor. Charles Van Brunt,

Has Attorheg.

Patented Feb. 26, 1929.

UNITED STATES PATENT OFFICE.

CHARLES VAN BRUNT, OF SCHENECTADY, NEW YORK. ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A COBPORATION OF NEW YORK.

PROCESS QF CLARIFYING OIL.

Application led Iaroh 3, 1924, Serial No. 696,655. Renewed November 24, 1928.

My presentvinvention constitutes an improvement in the process oi clarifying oil with water glass, which is described in my prior application Serial No. 746,040 tiled October 29, 1924 which is a continuation in part of application Serial No. 508,016, liled September 24, 1921, and which .is particularly applicable to the purifica-tion oi spent lubricating oil from automobile crank cases.

The suspended matter in spent lubricating oil consists largely of carbonaceous matter and water together with some abraded metal and roaddust. 1t is so iinely divided that it settles out only with extreme slowness. In accordance with the process described in this prior application, the iinely divided suspended matter is removed from the oil by treatment with an aqueous solution ot' an alkali silicate such as sodium silicate of the water glass of commerce. lhe dirty oil is mixed with the water glass, 'and the mixture then is floated upon water. Under the influence of the water glass, the solid mattei' becomes wetted, separates from the oil, and sinks into the water forming a sludge which is easily removed.

In the case of some crank case oils, separation and settling of suspended matteroccurs much more slowl than in the case of other oils. It is the object of my invention to increase the rapidity of sludge separation and otherwise to improve the clarification process.

I have discovered that the oils which are not'` readily susceptible to treatment with water glass for the removal of suspended matter are rendered responsive by the addition of small amounts of substances of a resinous character, as for example, colophony. These substances are capable of saponification by lthe alkali constituent of the water glass, and their beneficial action apparently is due to the formation of the soap in contact with the suspended particles.

The accompanying drawing illustrates one form .of apparatus suitable for carrying out my invention. Fig. 1 shows part of the appa- 'ratus in front elevation and part in longitudinal section; Fig. 2 is a horizontal sectional detail view of a feed apparatus, and Fig. 3 is a cross-section of a mixing chamber taken on lines 3 3 of Fig. 1.

In carrying my discovery into etect, resinous material is added to the oil to be purified, preferably as a solution in a volatile solvent readily miscible with the oil. For example, in thepurification of crank case oil about 0.1 per centby weight of colophony (rosin) is added to the oil, the colophony being dissolved in a convenient quantity of benzol, carbon tetrachloride, or other suitable solvent.

In some cases it is advantageous to add to the resinuous material, other non-resinous saponifiable materials, as for example, stearic acid f with the object of improving the clarity or brightness of the product. For example, an amount of stearic acid substantially of equal weight to the rosin may be added.

Colophony consists largely of abiotic acid which combines with the easily dissociated water glass to form a soap (rosin soap).I The presence of this soap affects interfacial tension of oil and water glass 'layers in such,

a way as to render the-suspended articles to the si icate solube more easily wetted b tion. After the oil and t e solution of rosin have been thorou hly admixed with each other as described a ove, Water glass is added; for example, to one gallon of oil mixed with. rosin to be purified is added about from one to two ounces of water glass of a concentragon having a specific gravity'of 40 degrees e. glass solution are thoroughly admixed in any convenient way. v

As shown in the drawing, the water glass solution is introduced by a pump 1 from a conduit 2 into a mixer 4, the oil being simultaneously drawn in from a conduit 5.15 As best shown in Fig. 2, the pump 1 is provided with a. rotor 6 having a spiral groove. When oil is supplied at agconstant rate, this type of pump meters the water glass supply, and maintains a definite ratio between the oil and pump 1 is driven from the same source of power which drives the oil pump delivering The oil and this concentrated wateroil to the inlet 5. The groove 1n the rotor I then is proportioned to give the proper water glass feed. Mounted in common with the rotor on the shaft 7 are a numberof paddles. 8, which -thoroughl churn and mix the oil and water glass in t e chamber 4. The shaft may be rotated by any convenient means as represented by a belt 9 running over a pulley 95 water glass. Conveniently, the spiral groove Y Wheel 10. The mixture of oil and Water glass v Whatl claim as new and desire to secure 45 flows througha pipe 11 into asettling tank 12. A. separate partition 23 sets into tank 12 and is provided with baiiie plates 13 set at diierent heights from the bottom so that the oil will pass in a sinuous path under one partition and then over the next, then under the following and so on, as indicated. Under the oil and `water glass mixture is a body of Water 14 which preferably is maintained Warm by an electric heater 15, which is contained in a tubular sheath 16. A temperature ofabout 800 C. is preferred.

As described and claimed in my prior application Serial No. 746,640, the water glass and suspended matter separate' 'from the oil' and form a sludge with the water. The sludge preferably is kept from settling to the bottom of the tank 12 Where it Would accumulate and clog the tank. For example, a stirring device 17 is provided driven by a belt 18 engaging with a pulley wheel 19 on the stirring device shaft. The Water which carries suspended sludge through a pipe 20, clean water being introduced by a. pipe2l. The clean oilv is discharged through an outlet pipe 22.

As already mentioned, the separation of sludge from oil, which has been subjected to the high temperature and other deteriorating conditions of an internal combustion engine, occui's rapidly when an acid resin has been added to theA oil. Secondly; the sludge produced with' oils containing an acid resin usually is somewhat -ner and remains suspended in Water for a longer time than a sludge produced by the use of Water glass alone. This is an advantage when it isdesired to cause a continuous flow of the Water under the surface of the oil to be puriiied, in order to uninterruptedly carry away the sludge. The sludges from the resin treated oils. have a less tendency to form adhering crusts on the walls of the tanks.

is discharged y by Letters Patent of the United States is 1. The step in the process of removing solid matter from used crank case oil by an aqueous solution of Water glass, which consists in dissolving rosin in said oil previous to the Water glass treatment.

2. The` step in the process of reclaiming i spent mineral lubricating oil containing finely divided solid matter by an aqueous solution of sodium silicate, which consists in adding to said oil about one-tenth of one per cent Vof colophony, and about one-tenth of one per c ent of stearic acid by weight.

3. The step in the process of clarifying a contaminated mineral oil b causing solid matter to forni a sludge with water glass,v which consists in adding` an acid resin to said oil.

contaminated liquid petroleum product by tre'atinent with water glass, which consistsv in adding thereto prior to *saidv treatment about one-tenth of one per cent of rosin by Weight.

5. The step in the processof reclaiming used mineral lubricating oil by forming a sludge therein with Water glass, which consists in adding to said oil a solution of a fractional per cent by weight of rosin priorto theY 4. T he step in the process of clarifying a ing said oil with water glass to form a sludge therein, and finally removing the sludge by water in contact with the sludge containing oil.

In Witness whereof, I have hereunto set my hand this 29th day of February, 1924.

CHARLES VAN BRUNT. 

